An etching chamber with an auxiliary window, an etching method
By introducing an adjustable auxiliary window into the etching chamber, the problem of difficulty in process changes caused by the fixed chamber structure is solved, and the high compatibility and uniformity of the chamber are optimized, reducing production costs and the risk of equipment obsolescence.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JIANGSU LEUVEN INSTR CO LTD
- Filing Date
- 2022-12-31
- Publication Date
- 2026-06-26
AI Technical Summary
The existing etching chamber structure is fixed, making it difficult to adapt to the rapid updates and adjustments of different processes, resulting in difficulties in process changes, low equipment utilization, and high costs.
Design an etching chamber with an auxiliary window whose material, thickness, diameter, and surface curvature are adjustable. By adjusting the plasma distribution, different process requirements can be met. The chamber can be made of ceramic, metal, or yttrium oxide materials, and the mounting components can be detachably fixed inside the chamber.
It improves the compatibility and adjustment feasibility of the chamber, and the uniformity optimization is improved from 10% to 3%, effectively responding to process changes and reducing equipment obsolescence and production costs.
Smart Images
Figure CN116246927B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of plasma etching chamber technology, specifically relating to an etching chamber with an auxiliary window and an etching method. Background Technology
[0002] Current etching chamber designs are generally developed specifically for a particular process, resulting in a relatively fixed internal structure. This fixed structure presents several drawbacks when dealing with different processes, including poor adjustability to changes in chip manufacturing processes, slow development of new structures, and difficulty in meeting the rapid iteration demands of chip production. Adjusting the chamber structure also requires significant financial investment and a long development cycle, which can severely impact the progress of new process development.
[0003] Traditional chambers with fixed windows have essentially fixed process performance, making it relatively difficult to improve process parameters. There are relatively few ways to increase etching rate, and the accuracy requirements for process changes are high. Moreover, the process window after the change will be relatively narrow. Such chambers will have difficulty responding to customer product iterations, which can easily lead to reduced equipment utilization or even equipment obsolescence.
[0004] Figure 1 In a traditional chamber structure, the distance between the ESC and the window is fixed once the design is complete. This results in different performance when dealing with different processes. For example, the same chamber may exhibit significant differences in etching rate and uniformity when dealing with Metal Etch and Poly Etch. Consequently, chip manufacturers find it difficult to adjust the chamber to meet different process requirements when the chamber type is fixed, making it hard to maximize efficiency and utilize the chamber as effectively as possible to cope with process and production adjustments.
[0005] Figure 2 This refers to the uniformity of the chamber structure in handling different processes. Based on actual data, we can see that when a fixed chamber structure is used to handle different processes, the specific process parameters will vary significantly. This greatly limits the chamber's adaptability and brings great difficulties and high costs to the production customers in adjusting their products. Summary of the Invention
[0006] Technical problem solved: In order to improve the structural adjustability and ease of adjustment of the chamber, this invention discloses an etching chamber with an auxiliary window and a corresponding etching method. The material, thickness, diameter, surface curvature and chamfer radius of the auxiliary window can be adjusted according to the actual process performance to cope with changes in different processes by customers, which greatly improves the compatibility of the chamber and the feasibility of rapid adjustment.
[0007] Technical solution:
[0008] An etching chamber with an auxiliary window, the etching chamber comprising a chamber body, a mounting assembly, and an auxiliary window detachably mounted within the chamber body via the mounting assembly;
[0009] The auxiliary window is fixed to the inside of the chamber cover by an installation assembly, and there is a gap between it and the electrostatic clamp. The cross-section of the auxiliary window completely covers the cross-section of the electrostatic clamp, and the center point of the auxiliary window and the center point of the electrostatic clamp are on the same vertical line.
[0010] During the etching process, the plasma distribution characteristics within the chamber are altered by adjusting the shape and size of the auxiliary window to meet different etching process requirements.
[0011] Furthermore, the auxiliary window is made of ceramic.
[0012] Furthermore, the auxiliary window is made of metal.
[0013] Furthermore, the auxiliary window is made of yttrium oxide.
[0014] Furthermore, an insulating layer is coated on the outer surface of the auxiliary window.
[0015] Furthermore, the auxiliary window is in the shape of a trapezoidal disc, with its bottom surface near the upper cover of the chamber and its top surface near the electrostatic clamp.
[0016] The adjustment parameters for the auxiliary window include material, thickness, diameter, and edge slope.
[0017] Furthermore, the diameter of the auxiliary window ranges from 0.5d to 1.5d; d is the diameter of the electrostatic chuck.
[0018] Furthermore, the diameter of the auxiliary window ranges from 100mm to 400mm; the thickness of the auxiliary window ranges from 10mm to 30mm.
[0019] Furthermore, the auxiliary window is in the shape of an arc-shaped disc, with the arc surface approaching and convex toward the electrostatic clamp.
[0020] The adjustment parameters of the auxiliary window include material, thickness, diameter, and curvature of the arc surface.
[0021] Furthermore, the auxiliary window is in the shape of a concave disc, with its arc surface close to the electrostatic clamp and convex toward the upper cover of the chamber;
[0022] The adjustment parameters of the auxiliary window include material, thickness, diameter, curvature of the arc surface, and edge slope.
[0023] Furthermore, the mounting assembly includes an auxiliary port;
[0024] The auxiliary pipe has a first end and a second end in the vertical direction. The first end is vertically connected to the pipe opening on the upper cover of the chamber, and the outer surface of the second end is provided with threads. The auxiliary window has a screw hole at the center, and the auxiliary pipe is screwed into the screw hole at the center of the auxiliary window to fix the auxiliary window to the inside of the upper cover of the chamber.
[0025] Furthermore, a partition is provided between the auxiliary window and the chamber cover.
[0026] Furthermore, the mounting assembly includes an auxiliary nozzle; a through hole is provided at the center of the auxiliary window; the positions and dimensions of the auxiliary nozzle and the through hole correspond to each other;
[0027] The auxiliary window has a protruding buckle on the end face of the chamber cover, and the chamber cover has a groove on the end face of the auxiliary window. The buckle and the groove are positioned and sized in correspondence.
[0028] The auxiliary window is fixed to the bottom of the chamber cover by snapping into the groove, and the auxiliary tube is inserted into and completely fills the through hole.
[0029] Furthermore, both the buckle and the groove are L-shaped.
[0030] The present invention also mentions an etching method, which is performed based on an etching chamber with an auxiliary window as described above;
[0031] The etching method includes the following steps:
[0032] S1. Obtain process parameters, calculate the ideal plasma distribution model above the electrostatic chuck based on the process parameters, and extract the shape parameters of the plasma distribution under the ideal state.
[0033] S2, calculate the process performance of auxiliary windows with different diameters and thicknesses, and select the shape parameters of the auxiliary disk under ideal conditions based on complementarity;
[0034] S3. Based on the shape parameters of the auxiliary disk under ideal conditions, select the appropriate auxiliary disk and install it inside the chamber cover.
[0035] S4 performs the etching process to check the uniformity of the wafer.
[0036] Beneficial effects:
[0037] First, the etching chamber of the present invention with auxiliary windows allows for adjustments to the material, thickness, diameter, surface curvature, and chamfer radius of the auxiliary windows based on the actual process performance, thus addressing customer changes to different processes and greatly improving the chamber's compatibility and rapid adjustment feasibility.
[0038] Secondly, the etching chamber with auxiliary window of the present invention optimizes the uniformity of the chamber from the traditional 10% to about 3%, which can effectively improve the uniformity performance of the chamber in response to different processes. Attached Figure Description
[0039] Figure 1 This is a schematic diagram of a traditional etching chamber.
[0040] Figure 2 This is a schematic diagram showing the uniformity performance of a traditional etching chamber when dealing with two different processes.
[0041] Figure 3 A schematic diagram showing the uniformity distribution of the etching chamber with fixed parameters.
[0042] Figure 4 The figures show a structural comparison between a conventional etching chamber and an etching chamber with an auxiliary window according to an embodiment of the present invention; in the figures, (a) is a structural schematic diagram of a conventional etching chamber, and (b) is a structural schematic diagram of an etching chamber with an auxiliary window according to an embodiment of the present invention.
[0043] Figure 5 This is a schematic diagram illustrating the uniformity performance of a traditional etching chamber for testing processes.
[0044] Figure 6 This is a schematic diagram illustrating the uniformity of an etching chamber with an auxiliary window in an embodiment of the present invention for testing processes.
[0045] Figure 7 This is a structural schematic diagram of one type of trapezoidal disc-shaped auxiliary window;
[0046] Figure 8 A schematic diagram of an auxiliary window in the form of another trapezoidal disc;
[0047] Figure 9 A schematic diagram of the structure of an auxiliary window in the form of a curved disc;
[0048] Figure 10 A schematic diagram of an auxiliary window in the form of a concave disc.
[0049] Figure 11 This is a flowchart illustrating the etching process of an etching chamber with an auxiliary window according to an embodiment of the present invention.
[0050] Figure 12 A structural diagram of the auxiliary window installation using a spiral locking mechanism;
[0051] Figure 13 A structural diagram for the installation of an auxiliary window using a snap-fit method;
[0052] Figure 14 This is a schematic diagram showing the manufacturing process of the auxiliary window (PAW) under different diameters and thicknesses.
[0053] Figure 15 A schematic diagram illustrating the impact of different PAW convex and concave structures on the process map;
[0054] Figure 16 A schematic diagram of process data for PAW under different conditions;
[0055] Figure 17 This is a schematic diagram illustrating the data uniformity results for PAW4. Detailed Implementation
[0056] The following embodiments are provided to enable those skilled in the art to more fully understand the present invention, but do not limit the invention in any way.
[0057] This embodiment discloses an etching chamber with an auxiliary window. The etching chamber includes a chamber body, a mounting assembly, and an auxiliary window detachably mounted within the chamber body via the mounting assembly. The auxiliary window is fixed to the inside of the chamber cover by the mounting assembly, with a gap between it and the electrostatic chuck. The cross-section of the auxiliary window completely covers the cross-section of the electrostatic chuck, and the center point of the auxiliary window and the center point of the electrostatic chuck are located on the same vertical line. During the etching process, the plasma distribution characteristics within the chamber are altered by adjusting the shape and size of the auxiliary window to meet different etching process requirements. Figure 4 This is a schematic diagram comparing the structure of a traditional etching chamber and an etching chamber with an auxiliary window according to an embodiment of the present invention.
[0058] Figure 3 This is a schematic diagram showing the uniformity distribution of an etching chamber with fixed parameters. It can be observed that the ER (Effect Reduction) at the wafer edge is significantly higher, which can greatly affect product uniformity. This embodiment primarily relies on the rapid installation of different types of auxiliary windows (PAWs) to modify the plasma morphology and meet process requirements, thus successfully applying a method for addressing new process development in the chamber. To address the development of different processes in the chamber, relevant auxiliary windows (PAWs) can be selected based on the specific performance of the process to improve related process performance. PAWs come in various forms; PAW thickness, edge angles, lower surface shape, and window locking methods can all be adjusted according to specific parameter requirements. This embodiment proposes several commonly used auxiliary window structures, as follows:
[0059] 1. PAW format 1, such as Figure 7 As shown: It is in the form of a trapezoidal disc, with its bottom surface close to the chamber cover and its top surface close to the electrostatic clamping plate; at this time, the adjustment parameters of the auxiliary window include material, thickness, diameter and edge slope, especially the edge slope can be adjusted according to process requirements.
[0060] 2. PAW form 2, such as Figure 8As shown: The PAW is in trapezoidal disk form. Adjusting the disk diameter allows for adaptation to different process data requirements. It can be seen that although PAW form 2 and PAW form 1 are both trapezoidal disks, the plasma distribution pattern changes significantly because the disk diameter is smaller than the electrostatic chuck diameter. In practical applications, the PAW diameter can be any size from 100mm to 400mm, generally chosen as a multiple of ESC (ESC = 300). For example: PAW diameter 1 = 150mm, PAW diameter 2 = 200mm, PAW diameter 3 = 250mm, PAW diameter 4 = 300mm, PAW diameter 5 = 350mm. The thickness can be any size from 10mm to 30mm, generally in 5mm increments. For example: PAW thickness 1 = 10mm, PAW thickness 2 = 15mm, PAW thickness 3 = 20mm, PAW thickness 4 = 25mm, PAW thickness 5 = 30mm. Optimal process data is tested with different diameters and thicknesses. The diameter of the auxiliary window ranges from 0.5d to 1.5d; d is the diameter of the electrostatic clamp.
[0061] 3. PAW form 3, such as Figure 9 As shown: The curved surface is in the form of a disc, with the curved surface approaching and convex towards the electrostatic clamp. At this time, the adjustment parameters of the auxiliary window include material, thickness, diameter and curvature of the curved surface. In particular, different curvatures of the curved surface can be selected according to specific process data.
[0062] 4. PAW format 4, such as Figure 10 As shown: The concave disc shape has an arc surface close to the electrostatic clamp and convex towards the top cover of the chamber. At this time, the adjustment parameters of the auxiliary window include material, thickness, diameter, curvature of the arc surface and edge slope. In particular, the concave curvature can be adjusted to meet the relevant process requirements.
[0063] Due to temperature requirements and the fact that the PAW (polyaluminum oxide) comes into direct contact with the plasma, the PAW operates at a relatively high temperature, making it less prone to the adhesion of byproducts. Simultaneously, during process cleanup in the chamber, the relevant clean gases effectively remove the PAW, ensuring its cleanliness and meeting production needs.
[0064] Considering the extensive plasma contact required by the PAW within the chamber, it necessitates the use of corrosion-resistant and bombardment-resistant materials. PAWs typically employ ceramics (AlO, AlN), metals (Al, SUS), Al+Y2O3, and ceramic+Y2O3. Since both the upper and lower parts of the PAW are insulated, there is no arcing risk, and no additional grounding is needed. Preferably, an insulating layer can be applied to the outer surface of the auxiliary window to further enhance insulation.
[0065] The connection between the PAW and Process window can be achieved using either a bayonet connection or a spiral locking mechanism, as detailed below. Figure 12 and Figure 13 As shown.
[0066] For helical locking methods, such as Figure 12 As shown, exemplarily, the mounting assembly includes an auxiliary port; the auxiliary port has a first end and a second end in the vertical direction, the first end being vertically connected to the port of the chamber cover, and the outer surface of the second end being provided with threads; a screw hole is provided at the center of the auxiliary window, and the auxiliary port is screwed into the screw hole at the center of the auxiliary window, so that the auxiliary window is fixed to the inside of the chamber cover. Preferably, a partition is provided between the auxiliary window and the chamber cover, and the distance between the auxiliary window and the chamber cover can be adjusted by changing the thickness of the partition.
[0067] For snap-on methods, such as Figure 13 As shown, exemplarily, the installation assembly includes an auxiliary port; a through hole is provided at the center of the auxiliary window; the position and size of the auxiliary port and the through hole correspond; a buckle is provided protruding on the end face of the auxiliary window near the chamber cover, and a groove is provided on the end face of the chamber cover facing the auxiliary window, the position and size of the buckle and the groove correspond; the auxiliary window is fixed to the underside of the chamber cover by the buckle being inserted into the groove, and the auxiliary port is inserted into and completely fills the through hole.
[0068] Three etching processes were randomly selected and executed using a traditional etching chamber and an etching chamber with an auxiliary window as described in this embodiment. By adding a PAW (Process Assist window), the plasma distribution inside the chamber can be effectively adjusted, thereby optimizing process uniformity. Actual data shows that the installation of the PAW significantly improves product uniformity, as detailed below. Figure 5 and Figure 6 As shown. By Figure 5 and Figure 6 The data shows that the process uniformity without PAW is 10%, while the uniformity of the chamber is optimized to about 3% after PAW is installed. This demonstrates that PAW can effectively improve the uniformity performance of the chamber in response to different processes.
[0069] See Figure 11 The present invention also mentions an etching method, which is performed based on an etching chamber with an auxiliary window as described above;
[0070] The etching method includes the following steps:
[0071] S1. Obtain process parameters, calculate the ideal plasma distribution model above the electrostatic chuck based on the process parameters, and extract the shape parameters of the plasma distribution under the ideal state.
[0072] S2, based on complementarity, calculate the shape parameters of the auxiliary disk under ideal conditions; Figure 14 This shows the process performance of PAW under different diameters and thicknesses.
[0073] Different PAW (Panel Wood) structures, both convex and concave, can affect the process map, such as... Figure 15 As shown.
[0074] S3. Based on the shape parameters of the auxiliary disk under ideal conditions, select the appropriate auxiliary disk and install it inside the chamber cover; test the process performance of PAW under different conditions. Figure 16 Process data for PAW under different conditions. Figure 16 The specific values are only for the purpose of indicating the performance of the process. These values will change under different etching processes and chamber structures.
[0075] S4, perform the etching process and check the wafer uniformity. Based on the above data, we can conclude that PAW condition 4 has the best data uniformity results. Therefore, we can complete the PAW development for this process. The test results are as follows: Figure 17 As shown.
[0076] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.
Claims
1. An etch chamber having an auxiliary window, comprising: The etching chamber includes a chamber body, a mounting assembly, and an auxiliary window that is detachably mounted in the chamber body via the mounting assembly. The auxiliary window is fixed to the inside of the chamber cover by an installation assembly, and there is a gap between it and the electrostatic clamp. The cross-section of the auxiliary window completely covers the cross-section of the electrostatic clamp, and the center point of the auxiliary window and the center point of the electrostatic clamp are on the same vertical line. During the etching process, the plasma distribution characteristics within the chamber are altered by adjusting the shape and size of the auxiliary window to meet different etching process requirements; The auxiliary window is made of ceramic, metal, or yttrium oxide; An insulating layer is applied to the outer surface of the auxiliary window; The auxiliary window is disc-shaped, with its bottom surface near the chamber cover and its top surface near the electrostatic clamp. The adjustment parameters of the auxiliary window include material, thickness, and diameter; The etching chamber performs the following steps: S1. Obtain process parameters, calculate the ideal plasma distribution model above the electrostatic chuck based on the process parameters, and extract the shape parameters of the plasma distribution under the ideal state. S2, calculate the process performance of auxiliary windows with different diameters and thicknesses, and select the shape parameters of the auxiliary disk under ideal conditions based on complementarity; S3. Based on the shape parameters of the auxiliary disk under ideal conditions, select the appropriate auxiliary disk and install it inside the chamber cover. S4 performs the etching process to check the uniformity of the wafer.
2. The etch chamber with auxiliary windows of claim 1, wherein, The diameter of the auxiliary window ranges from 100mm to 400mm; the thickness of the auxiliary window ranges from 10mm to 30mm.
3. The etch chamber with auxiliary windows of claim 1, wherein, The auxiliary window is in the shape of an arc-shaped disc, with the arc surface close to and convex toward the electrostatic clamp. The adjustment parameters of the auxiliary window include material, thickness, diameter, and curvature of the arc surface.
4. The etch chamber with auxiliary windows of claim 1, wherein, The auxiliary window is in the shape of a trapezoidal disc, and the adjustment parameters of the auxiliary window include material, thickness, diameter, and edge slope.
5. The etching chamber with an auxiliary window according to claim 1, characterized in that, The auxiliary window is in the shape of a concave disc, with its arc surface close to the electrostatic clamp and convex toward the upper cover of the chamber. The adjustment parameters of the auxiliary window include material, thickness, diameter, curvature of the arc surface, and edge slope.
6. The etching chamber with an auxiliary window according to claim 1, characterized in that, The installation components include auxiliary ports; The auxiliary pipe has a first end and a second end in the vertical direction. The first end is vertically connected to the pipe opening on the upper cover of the chamber, and the outer surface of the second end is provided with threads. The auxiliary window has a screw hole at the center, and the auxiliary pipe is screwed into the screw hole at the center of the auxiliary window to fix the auxiliary window to the inside of the upper cover of the chamber.
7. The etching chamber with an auxiliary window according to claim 6, characterized in that, A partition is provided between the auxiliary window and the chamber cover.
8. The etching chamber with an auxiliary window according to claim 1, characterized in that, The installation assembly includes an auxiliary pipe opening; a through hole is provided at the center of the auxiliary window; the positions and dimensions of the auxiliary pipe opening and the through hole correspond to each other; The auxiliary window has a protruding buckle on the end face of the chamber cover, and the chamber cover has a groove on the end face of the auxiliary window. The buckle and the groove are positioned and sized in correspondence. The auxiliary window is fixed to the bottom of the chamber cover by snapping into the groove, and the auxiliary tube is inserted into and completely fills the through hole.
9. The etching chamber with an auxiliary window according to claim 8, characterized in that, Both the buckle and the groove are L-shaped.
10. An etching method, characterized in that, The etching method is performed based on an etching chamber with an auxiliary window as described in any one of claims 1-9; The etching method includes the following steps: S1. Obtain process parameters, calculate the ideal plasma distribution model above the electrostatic chuck based on the process parameters, and extract the shape parameters of the plasma distribution under the ideal state. S2, calculate the process performance of auxiliary windows with different diameters and thicknesses, and select the shape parameters of the auxiliary disk under ideal conditions based on complementarity; S3. Based on the shape parameters of the auxiliary disk under ideal conditions, select the appropriate auxiliary disk and install it inside the chamber cover. S4 performs the etching process to check the uniformity of the wafer.